Financial instruments (Tables)

6 Months Ended

Jun. 30, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Values of Derivative Instruments Designated as Hedging Instruments

The following table presents the locations in the condensed consolidated balance sheet and fair value of derivative financial instruments as of June 30, 2019 and December 31, 2018:

	June 30, 2019		December 31, 2018
	Fair Value
	(Dollars in thousands)
Asset derivatives:
Designated foreign currency forward contracts	$	1,344	$	1,216
Non-designated foreign currency forward contracts	159		106
Cross-currency interest rate swap	21,156		14,728
Prepaid expenses and other current assets	22,659		16,050
Total asset derivatives	$	22,659	$	16,050
Liability derivatives:
Designated foreign currency forward contracts	$	992	$	524
Non-designated foreign currency forward contracts	131		264
Other current liabilities	1,123		788
Cross-currency interest rate swap	6,152		7,793
Other liabilities	6,152		7,793
Total liability derivatives	$	7,275	$	8,581